If you're just trying to find a good used starter boat, I'd go out and see what's available (what people are selling) and then look the boats up on Eddy Flower
. Once you think you've found a good one, then ask here (or other forums) what people think of it. There are so many different boats, asking for people to list what they like won't get you very far in actually buying a boat. Besides, it's very dependent on the person and what kind of water they paddle too.
In general a river runner will be easier to learn with, but many people learn in playboats too. You also want something at least semi-recent.
That said, there are some boats that were/are really popular. The EZ and the Inazone come to mind. The RPM too, but I personally wouldn't recommend an RPM even though lots of people still seem to like them. Boat design has advanced a lot since the RPM came out.